I like the first half of the idea, which is to buy HBD in order to get 20% interest.

Here is an idea for what to do with the interest.

Buy SPS to be donated to Splinterlands for the specific purpose of BOOSTING the amount of SPS being given in rewards to players each day. This will inject value in the ecosystem by using the DAO's interest to directly fuel the rewards given to players. The SPS given this way would be bought from the market first so no extra inflation. It is also 100% sustainable over the long term.